Question

Arun and balu can do a piece of work in 9 and 12 days respectively. Starting with arun, they both work alternately. How long will it take for the work to be completed?

Answer 1

my answer is wrong i am sorry

Answer 2

Answer:

Suppose whole work is 1

And time is X

in 9 days Arun does = 1

in 1 " " " =1/9

in X " " " =X/9

Thus Balu does his work in X days

X/12 days

Then, X/9+X/12= 1

21X/108=1

X=108/21

X=36/7